I have a beer light that uses a 12v 5w bulb. I have an old charger that outputs at 18vdc 400mA. I have cut the head off the charger and made a simple circuit with the bulb.
It obviously works but the voltage is too high for the bulb. I bought a volt meter today and the voltage in the circuit is actually about 25v. I bought a 10 ohm resistor from maplinhttp://www.maplin.co.uk/10k-ohm-to-30-o ... ors-341625
When i attach it to the circuit, (before the bulb), and switch on, the bulb doesn't glow. But my volt meter reads a voltage of about 24.5v.
I thought my 10ohm resistor would reduce my (anticipated) 18v voltage down to about 12v but none of that has worked and i can't understand why the bulb won't glow?
Any thoughts? I presume i'm doing something very wrong.
Any help would be greatly appreciated.